Dual-Ion Co-Regulation System Enabling High-Performance Electrochemical Artificial Yarn Muscles with Energy-Free Catch States

Highlights The dual-ion co-regulation system shortens ion migration pathways, which endow the yarn muscle with high contractile stroke (34.7%) and contractile rate (9.4% s−1), more than twice that of the “rocking-chair” -type ion migration yarn muscles. The yarn muscle shows high isometric stress of 18.4 MPa (61 times that of skeletal muscles) and 8 times the isometric stress of the “rocking-chair” -type yarn muscles at a higher frequency. The intercalation reaction between \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{PF}}_{6}^{ - }$$\end{document}PF6-and collapsed carbon nanotubes allows the yarn muscle to achieve an energy-free high-tension catch state Supplementary Information The online version contains supplementary material available at 10.1007/s40820-023-01133-2.


Supplementary Figures and Tables
The ex-situ Raman peak shift of CNT yarn at different charged and discharged states by using CV scan at 10 mV s −1 . The ex-situ Raman spectroscopy was performed by using a HeNe laser with a wavelength of 532 nm. The G peak can be fitted into three peaks: peaks 1, 2, and 3 are assigned to the G peak after splitting, the appeared new peak, and the D′ peak, respectively

Fig. S5
The Raman shifts of the fitted peaks in Fig. S2. The G peak (peak 1) blueshifted slightly from 1585 cm −1 to 1590 cm −1 with increasing the potential from 3 V to 4.2 V. As the coiled CNT yarn was charged to 5 V, the split new peak (peak 2) and the G peak after splitting blue-shifted to the maximum of 1612 and 1603 cm −1 , respectively. The two peaks gradually combined into one peak for the G band at 1588 cm −1 during the potential back to 3 V. The D′ peak (peak 3) was stable during the charge and discharge process.  The decay rates of the catch index of the DIYM when the power was off for 500 s. The artificial muscle yarn was charged from 3 V at a scan rate of 50 mV s −1 to 4.5, 4.8, and 5 V, respectively, and then the power is off. The catch index at different end potentials of 4.5, 4.8, and 5 V were 91.2%, 95.8%, and 96.4%, respectively, and the decay rates of the catch index were 0.02, 0.008, and 0.007 %ꞏs −1 , respectively

Fig. S10
The curves of contractile stroke of the DIYM versus time at different scan rates during CV measurements from 3 V to 5 V at the applied load of 10 MPa   The curves of contractile stroke of the RCYM versus time at different on/off frequencies when a 3 to 5 V square wave with a 50% duty cycle and tension stress of 10 MPa were applied

Fig. S16
The effects of applied tensions on the contractile stroke and the generated contraction work of the DIYM when a 3 to 5 V square wave at 0.14 Hz with a 72% duty cycle (5 V for 5 s and 3 V for 2 s) were applied

Fig. S17
The cyclic stability of the DIYM. The potential of 5 V was held for about 0.9 s, then switched to 3 V for about 0.9 s, and the response frequency was 0.24 Hz, while a pre-tensile tension of 10 MPa was applied.

Fig. S18
The cyclic stability of the DIYM. The potential of 5 V was held for about 0.9 s, then switched to 3 V for about 0.9 s, and the response frequency was 0.24 Hz, while a pre-tensile tension of 10 MPa was applied.

Fig. S19
The mechanical properties of the CNT yarns before and after 10,000 continuous rapid contraction cycles. (a) The stress-strain curves. (b) The comparison of the failure strain and the breaking strength between the artificial muscle before and after actuating. The failure strain and the breaking strength of the CNT yarn before the test are 109. 3% and 193.4 MPa, respectively. And, after 10,000 continuous rapid contraction cycles, the failure strain and the breaking strength of the CNT yarn before the test are 82.4% and 251.7 MPa, respectively.   The curves of isometric stress of the RCYM versus time at different on/off frequencies when a 3 to 5 V square wave with a 50% duty cycle and tension stress of 10 MPa were applied

Fig. S24
The comparison of the isometric stress rate of the DIYM and RCYM at different frequencies when the 3−5 V and 0.2−2.2 V square wave were applied for DIYM and RCYM, respectively, and tension stress was 10 MPa

Fig. S25
The isometric stress of the DIYM under square waves with different potentials at 0.1 Hz. The potential for the returning process of yarn muscle was 3 V and the tension stress of was10 MPa